Novel organic monotectic alloy and its thermal, physicochemical, and microstructural studies

Abstract

The phase diagram study of an organic analogue of a nonmetal–nonmetal system involving 4-bromochlorobenzene and resorcinol shows the formation of a eutectic and a monotectic. The phase equilibrium shows the large miscibility gap region with the consolute temperature 143.0 °C. Growth kinetics of the eutectic, the monotectic and the pure components studied at different undercooling, suggests the applicability of Hillig–Turnbull’s equation. For binary materials and parent compounds, the heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions were calculated from the enthalpy of fusion values determined by the DSC method. The solid–liquid interfacial energy shows the applicability of Cahn’s wetting condition. The effects of solid–liquid interfacial energy on solidification behaviour of monotectic alloy have also been discussed. The microstructures of monotectic and eutectic show the uniform array of droplets and broken lamella, respectively.